The present invention relates to a ball valve. More particularly, the present invention relates to a seal and a rotatable ball contained within a housing which seal and ball are blocked against movement out of the housing when connecting sleeves are disconnected from the housing.
Rotatable balls which selectively open and close an axial passageway in a ball valve housing are commonly used in fluid piping systems. It is desirable to provide a ball valve which can be disconnected from the system without causing the ball or seals about the ball to fly out of the housing, i.e., a blocked ball valve. It is also desirable to provide an apparatus for a ball valve which prevents outward movement of the ball but permits the seals about the ball, often carried by a seal carrier, to be adjustably biased against the ball to effectuate a tight fluid seal about the ball.
Numerous devices have been proposed which block a seal and ball in place. However, some of these devices have not provided any apparatus for urging the seal against the surface of the ball to improve sealing about the ball.
One known device is disclosed in U.S. Pat. No. 4,023,773 issued to Wise. The Wise patent discloses a true union ball valve in which a seal and a seal carrier are blocked by a split locking ring positioned against the seal carrier. The locking ring has an abutment thereon which engages an abutment in a housing to hold the locking ring in place. A cam ring is inserted between the seal carrier and the locking ring for expanding the locking ring into a groove which carries the abutment in the housing. A bonding socket is urged against the locking ring and the cam ring by a flanged nut thereby urging the seal on the seal carrier against the surface of a ball. A device of this type however does not permit free movement of the seal carrier without movement of the cam ring and the locking ring.
Another device is disclosed in U.S. Pat. No. 4,059,250 issued to Guldener et al. The Guldener et al patent discloses a seal for a ball valve which is carried by an insert ring. The insert ring is held in place within a housing for the valve by a bayonet-type connection including tabs on the insert ring which tabs slide within recesses on an inside peripheral surface of the housing. The recesses communicate with an annular groove on the inside peripheral surface of the housing. The ring is inserted into the housing and turned so that the tabs engage the annular groove in the housing to prevent movement of the insert ring away from the ball. However, a blocking device of this type may be inserted within the ball valve housing without rotating and locking the insert ring such that the ball is likely to fly out of the housing when the ball valve housing is disconnected from a connecting member.
A further device for holding a seal and a rotatable ball within a valve housing is disclosed in U.S. Pat. No. 3,669,406 issued to Moore. In the Mbore patent, the seal for the ball is held in place by a resilient annular retaining ring which abuts an outside surface of the seal. The retaining ring is received in an annular recess formed in the housing. A device of this type, however, does not permit movement of the seal on the ball without flexure of the resilient retaining ring. Since the retaining ring must move axially along with the seal, the resiliency of the retaining ring determines the maximum force which can be exerted by the seal against the ball.
A further device is disclosed in U.S. Pat. No. 3,458,171 issued to Urban which discloses a seat ring for a ball valve which is inserted into one end of a housing for a rotatable ball. An annular cap member is provided to maintain the seat ring in abutting engagement with the ball. The annular cap member is secured in position by a plurality of set screws which engage a wedge shaped groove in an outer peripheral surface of the cap member.
U.S. Pat. No. 3,420,408 issued to Wilcox discloses a fluid-tight coupling in which the conduits through which fluid flows to each half of the coupling may be misaligned without leakage of the fluid. A seal member arranged in a housing is pressed by a spring against a spherical end of one half of the coupling. The seal member is aligned by an annular extension of a first portion of the housing which is threaded to a second portion of the housing.
A further device is disclosed in U.S. Pat. No. 3,214,131 issued to Boldt et al which discloses a valve having an apparatus for moving a guiding bushing into a sealing position against the surface of a rotating valve element. The apparatus comprises a member arranged in a cyclindrical bore of the valve housing. The member is provided with a wedge or inclined surface cooperating with a corresponding wedge on the guiding bushing. Displacement of the member is accomplished by adjusting a screw which moves the wedge or inclined surface on the member radially into or out of engagement with the wedge on the guiding bushing.
Other devices for blocking ball valves within a housing are disclosed in U.S. Pat. Nos. 3,284,046 issued to Allenbaugh, Jr; 3,288,430 issued to Priese; 3,653,631 issued to Hurst; 4,172,584 issued to Legris; and 4,175,726 issued to Richards.
Accordingly, it is an object of the present invention to provide a ball valve which includes an arrangement for retaining a seal within a housing for the ball valve while permitting movement of the seal toward a surface of a rotatable ball independently of the arrangement for retaining the seal and the ball.
A further object of the present invention is to provide a ball valve which cannot be assembled within a fluid system without blocking the ball and seal against movement out of a ball valve housing.
It is still a further object of the present invention to provide a ball valve which includes a blocked seal and seal carrier but permits the seal carrier to be biased against the surface of a ball by a connecting sleeve pipe when the connecting sleeve is secured to a ball valve housing.
Another object of the present invention is to provide an arrangement for blocking a ball valve which is simple and inexpensive to manufacture yet maintains a ball and associated seals within a housing.
These and other objects of the present invention are achieved by a ball valve having a housing with an axial passageway through the housing. A rotatable ball arranged within the axial passageway selectively opens and closes the axial passageway and a seal arranged at one end of the housing within the axial passageway is adapted to abut a surface on the rotatable ball to seal the ball against fluid leakage. A blocking member threadedly connected within the passageway prevents axial movement of the seal toward the one end of the housing while permitting axial movement of the seal toward the surface of the ball independently of the blocking member under the urging of a seal pressurizing member.
In a preferred embodiment, the seal is carried on a first radial surface of a seal carrier and the blocking member comprises an annular ring arranged in an annular groove in an outer peripheral surface of the seal carrier. The annular groove extends along a portion of the axial length of the seal carrier from a second radial surface of the seal carrier facing the one end of the housing. An external diameter of the annular groove is less than an internal diameter of the annular ring. Also the axial length of the annular groove is preferably greater than the axial length of the annular ring.
Further, in the preferred embodiment of the present invention the annular ring includes a threaded outer peripheral surface which is secured to internal threads arranged within the housing adjacent the one end.
Still further, the seal pressurizing member is a connecting sleeve having a flange at a first end with a first side of the flange being adapted to abut the second radial surface of the seal carrier to urge the seal carrier towards the rotatable ball. The connecting sleeve is secured to the ball valve housing by a clamping nut having internal threads adapted to engage threads on an outer peripheral surface of the housing adjacent the one end. The clamping nut has an inwardly directed flange which engages a second side of the flange on the connecting member to adjustably urge the first side of the flange of connecting member into engagement with the second radial surface of the seal carrier as the nut is secured to the housing.